Abstract
[Purpose] The aim of this study was to investigate the relationship between symptoms of temporomandibular disorders (TMD) and upper quadrant posture measured by an ultrasound-based three-dimensional motion analyzer. [Subjects] The participants were 7 females with TMD symptoms (symptomatic group; mean age, 22.3 years) and 13 females without TMD symptoms (asymptomatic group; mean age, 23.3 years). [Methods] Outcome measures were the neck inclination angle (formed by a line connecting C7 and the ear tragus with a horizontal line), the angle of the shoulder (formed by a line connecting C7 and the acromial angle with a horizontal line), and the cranial rotation angle (formed by a line connecting the ear tragus and the corner of the eye with a horizontal line). The maximum range of mouth opening was measured using a scale. A significance level of 5% was used. [Results] The neck inclination angle of the symptomatic group was significantly smaller than that of the asymptomatic group in standing and in sitting. The maximum range of mouth opening of the symptomatic group was significantly smaller than that of the asymptomatic group. [Conclusion] TMD symptoms in young females were associated with head posture measured by an ultrasound-based three-dimensional motion analyzer.
